http://www.marineenginedigest.com/diy/8simplerules.htm

http://www.boated.com/topic.asp?TOPIC_ID=111643

http://www.indmar.com/About/ContactIndmar/Manual_2003_Presentweb.pdf

http://www.mercurymarine.com/_media/pdfs/serviceandwarranty/sterndrive-models/Non-EC/90-899883179-Maint.pdf

http://www.volvo.com/volvopenta/na/en-us/marine_leisure_engines/parts_service/publication_search/publication_search.htm

Tune-ups are a vital element in extending engine life. A weak ignition spark does a poor job "lighting the fire." As a result, not all of the fuel/air mixture burns. Not only do performance and fuel economy suffer, but unburned, abrasive hydrocarbons also deposit themselves on pistons and combustion chambers. An out of tune engine can also lead to pre-ignition / detonation which can cause severe piston damage.

Ambient air temperature in marine engine compartments is higher than the temperature of the air surrounding an automotive engine. All this heat in addition to the water contained in the bilge,produce an elevated humidty level with rampant corrosion of ignition components. These factors added to the hard work combine to push marine engines to the edge of the envelope.

In extreme cases, unburned gasoline washes lubricant off cylinder walls, causing excess heat and friction to score them. And when gasoline gets into the crankcase sump, it dilutes the oil, reducing lubrication even further. Rings begin to stick, which pulls the plug on compression. If the oil rings are damaged, the engine becomes an oil-burner.

Procedure:

Perform cylinder compression test. Remove and replace the following components:

• Distributor Cap
• Distributor Rotor
• High Tension Leads
• Spark Plugs (analyze plugs for problem signs)
• Distributor Ignition Module
• Alternator Drive Belt
• Fuel Filter(s)

Clean flame arrestor, set choke and idle speed (non fuel injected) and set engine to specifications. Connect to laptop Diacom and check for codes (where applicable).